Gender related pharmacokinetics of diltiazem in healthy subjects

The aim of this study was to investigate the gender-related pharmacokinetic differences after a single oral dose of diltiazem (120 mg) in 12 healthy subjects (6 males and 6 females). Kinetic parameters were calculated from serum concentrations obtained by means of a specific HPLC method. The total area under the concentration-time curve (AUC0-infinity) was 917.03 +/- 342.13 ng.h-1/ml for females and 1,192.97 +/- 329.93 ng.h-1/ml for males. Peak serum levels (Cmax) were 181.29 +/- 48.03 ng/ml and 194.29 +/- 93.81 for females and males, respectively. The time to reach maximum concentration (Tmax) was 2.2 +/- 0.8 h for both. The biological elimination t1/2 was 4.58 +/- 2.08 h and 5.59 +/- 2.44 h, showing an elimination rate (kel) of 0.174 +/- 0.062 h-1 and 0.149 +/- 0.075 h-1, and a mean residence time (MRT) of 8.56 +/- 1.94 h and 8.88 +/- 2.78 h for females and males, respectively. Male subjects showed higher values than females, but no significant difference was observed when comparing pharmacokinetic parameters by gender. Diltiazem was well tolerated by all subjects.